Interlockable dental dowel pin and repositioning gauge and method of using



p 1958 R. SPALTEN ET AL 2,851,728

INTERLOCKABLE DENTAL DOWEL PIN AND REPOSITIONING GAUGE AND METHOD OFusme Filed July 14 1954 TEEZ INVENTO TTOR EY INTERLOCKABLE DENTAL DOWELPIN AND REPOSITIONING GAUGE AND METHOD OF USING Robert Spalten, NewYork, N. Y., and Abraham B. Weinstein, Stamford, Conn., said Spaltenassignor to said Weinstein Application July 14, 1954, Serial No. 443,324

Claims. (Cl. 18--34.1) I

Our invention relates to dowel pins such as are used in indirect inlay,crown, precision splint, fixed and removable bridge techniques.

The dowel pins presently in use rely upon a taper to insure placement ofthe die in the model, some with a flat face on one side of the body toprevent rotation. The pin may be threaded to a slotted nut to hold thedie securely in place. However, a speck of dirt, stone or wax in theseat will prevent accurate reseating in the cast,

United States Patent 0 r Ce shown in dot-dash position 18 in Fig. 6 inorder that the gauge 17 may pass gauge 16 should the dowel pins roundthe arch of the mouth, as in Figs. 1 and 4. The stems 20 are serrated orknurled to aid in securing the dowel pin to the die metal as shown inFigs. 2 and 3.

In Figs. 1, 2 and 3, there is illustrated a single impression 30 made ofrubber mounted on a tray 32. This impression is made of the preparedteeth in the mouth.

In the particular impression, the die metal represents teeth 34, 36, 38,40 and 42 shown prepared as abutments for bridgework with thecorresponding dowel pins 35, 37,

' 39, 41 and 43 in place prior to pouring of the stone cast thusdestroying the relationship to adjacent and opposing teeth. The nut maybe tightened excessively, or its seat scored, which will destroy itsproper fit. The incidence of error is increased the more the die isremoved and reseated, and only when the dental restoration is completedis the degree of error manifest.

It is therefore an object of our invention to provide a means forpositive reseating of the dies and a means for relating the dies toadjacent and opposing teeth during the various stages of construction.Further objects are to provide a means for checking the relationshipbetween dies and their seats, without danger to accuracy; to providesimplicity of construction with ease of manipulation; to provide adesign for seating of the dies which will reduce production costs; toprovide greater durability in the die reseating means; to provide theutmost convenience in articulating the cast; and to provide a dowel pinhaving all the foregoing advantages and which perfects the singleimpression technique developed as an aid in dentistry and which extendsthe scope thereof to larger spans in the mouth than are possible withother known means.

We accomplish these and other objects and obtain our new results as willbe apparent from the device described in the following specification,particularly pointed out in the claims, and illustrated in theaccompanying drawing in which:

Fig. 1 is a plan view of our dowel pins with repositioning gauges in arubber impression, set in a wax box provided with bridging wax plugs.

Fig. 2 is a sectional view taken in the plane 2-2 of Fig. 1 through oneof the wax plugs.

Fig. 3 is a sectional view taken in the plane 33 of Fig. 1 through oneof the repositioning gauges.

Fig. 4 is a perspective view of a fragment of the stone model made fromthe rubber impression.

Fig. 5 is an enlarged fragmentary sectional view taken in the plane 5-5of Fig. 4 with access to the end of the pin formed by the wax plug.

Fig. 6 is an enlarged perspective view of one of the pins.

Fig. 7 is an enlarged perspective view of the pin with detachable metalseat.

As is shown in Fig. 6, the novel dowel pin 10 comprises a tapered body12 having an aperture 14 for the insertion of the repositioning gauge 16therethrough, as shown in Fig. 3. Some dowel pins are provided withapertures in relatively lower positions on the tapered body 44. Theimpression material 30 is silver plated, as at 46, to hold the die metalwhich is poured with the dowel pins in position. This position ismaintained by the repositioning gauges 16 and 17 which pass through theapertures in pins 35, 37, 39, 41 and 43, respectively. A wax box 48 isprepared for confining the casting, and the repositioning gauges may besupported in the walls thereof when the die metal is poured.

The heads of the dowel pins are rounded as at 22 to facilitate removalof the dowel pins from the stone cast. Bridging wax plugs 50 may beextended from the wax box wall to the rounded ends 22 to form recesses52 in the stone cast, which provide access to the rounded ends of thepins when the wax is melted. This is shown in Fig. 4.

The stone is cast and thereafter the wax is removed,

and slots 56 are cut to free adjacent dies. The gauges 16 and 17 arethen removed by pulling at their heads 19 and 21, respectively, whichare enlarged for this purpose. The gauges may be lightly coated with alubricant to facilitate removal. Then the gauge is inserted into therecess 52 and the rounded end 22 of the dowel pin gently pressedoutwardly to free the respective dowel pin from the stone cast. Thedowel pin may be similarly provided with a thin lubricating coat of oilto assist in freeing the pin.

By means of our invention, the dowel pins may be accurately reseated inthe cast and related to adjacent teeth during the processing ofbridgework. The repositioning gauges may be inserted in the respectiveapertures in the dowel pins to determine whether the tapered walls arefree of ioose particles that may be deposited during processing. Thus apositive check for accuracy is obtained without danger of damage to thestone cast.

The dowel pins are preferably made of flat stock which orients the dowelpins into their respective tapered sockets. Otherwise, if made inconical shape, it would be necessary to slowly revolve each dowel pinuntil the axis of the aperture is in line with the axis of therepositioning gauge.

A sleeve 60 provides an accurate fixed socket which is free of wear andjustifies the added expense. It can be made of thin sheet metal stock asshown in Fig. 7. It closely conforms to the tapered wall of the dowelpin and may be keyed, if round, to the dowel pin, to orient the dowelpin when inserted. Slight projections 62 may be formed in the outer wallof the sleeve to retain the sleeve to the cast stone wall and resistremoval when the dowel pin is ejected. A cut-out 64 may be provided forentrance of the repositioning gauge. By using a cut-out instead of afitted aperture in each sleeve for the retention pin, it is unnecessaryto closely fit each sleeve to each pin to align the two parts.

It will thus be seen that the dowel pins are not limited to any specificshape. The apertures and repositioning gauges need not be round. The pinmaterials may be hard brass, but other material may be used, such asstainless steel. Other methods of detachably interlocking the dowel pinto the repositioning gauges may be employed.

Having obtained the accuracy needed for the single impression technique,we have found that it is now possible, for the first time, to extend thesingle impression technique from single castings and small spans tolarge multiple abutment spans as a means of obtaining full mouthrehabilitation. This represents an advance in dentistry as apreventative remedy in contradistinction to the simple reparativeapproach that small span bridgework can provide. The ability to makeprecision splints and large span bridgework is invaluable in thetreatment of pyorrhea and the prevention of recurrent caries.

We have thus described our invention, but we desire it understood thatit is not confined to the particular forms or uses shown and described,the same merely being illustrative, and that the invention may becarried out in other ways without departing from the spirit of ourinvention, and, therefore, we claim broadly the right to employ allequivalent instrumentalities coming within the scope of the appendedclaims, and by means of which, objects of our invention are attained andnew results accomplished, as it is obvious that the particularembodiments herein shown and described are only some of the many thatcan be employed to attain these objects and accomplish these results.

We claim:

1. In the method of reproducing the condition of the mouth for forminginlays, crowns and fixed bridges after cutting the teeth in theappropriate shape, which comprises making a negative impression withshape retaining material in the mouth of the cut teeth, the step ofpositioning a dowel pin having a stern and a body with the stem in thenegative impression of each cut tooth, connecting a repositioning gaugeto the body thereof, forming dies of rigid material inside the negativeimpression of each cut tooth and about the stem of the dowel pin,forming a cast of rigid material about the bodies of the dowel pins andrepositioning gauges, removing the repositioning gauge from each dowelpin, removing the negative impression from the dies to expose thepositive replicas of each original cut tooth and removing each die fromthe cast of rigid material, whereby each die and attached dowel pin maybe reseated in the proper position in the cast of rigid material byreconnecting the repositioning gauge to the dowel pins, thus maintainingthe relationship between the various teeth in the construction of theinlays, crowns and fixed bridges.

2. The method of claim 1 including the step of covering the end of thedowel pin with a wax bridge leading to the outside of the mold prior toforming the cast of rigid material to facilitate removal of the dowelpin and associated die from the cast of rigid material.

3. The method of claim 1 including the step of providing the dowel pinswith removable metal sleeves which are retained in the cast of rigidmaterial when the dowel pins are withdrawn.

4. In combination, a dowel pin and repositioning gauge for detachableconnection thereto, said dowel pin having a locking means for rigidconnection to a die metal casting of a cut human tooth, said pintapering in width and depth towards the free end thereof to facilitateremoval from rigid material that is cast thereover and having anaperture in the free end for insertion of the repositioning gaugetherein, said repositioning gauge comprising a member of uniformcross-section.

5. The combination of claim 4 having a closely fitted and detachablemetal sleeve closely conforming to the tapered end of the dowel pinadjacent the gauge connecting portion, said sleeve having extendingmeans for securement to a cast of rigid material molded therearound.

References Cited in the file of this patent UNITED STATES PATENTS1,144,336 Whiteley June 22, 1915 1,507,024 Monson Sept. 2, 19242,274,060 Hart Feb. 24, 1942 2,310,830 Blair et al. Feb. 9, 19432,423,330 Levine July 1, 1947 2,433,889 Bryant Jan. 6, 1948 2,434,416Kohn et al. Jan. 13', 1948 2,576,206 Barth Nov. 27, 1951 2,648,136Lanigan Aug. 11, 1953

